Synthesis of Hyperbranched Polymers by Photoinduced Metal-Free ATRP

A novel synthetic strategy for the syntheses of hyperbranched homo and block copolymers was developed. By applying the photoinduced metal-free atom transfer radical polymerization (ATRP) using perylene as photocatalyst, monomer/inimer pairs were transformed into hyperbranched polymer structures under visible light irradiation. Using the halide functional groups in thus-formed structures as initiating sites, further polymerizations were also performed to construct the secondary segments successfully. The strategy described here enables the synthesis of such complex polymeric structures by a simple procedure, under mild and metal-free conditions. All polymers were characterized by spectroscopic and chromatographic techniques.